JPS62242624A - Antitumor agent - Google Patents

Abstract

NEW MATERIAL:A compound of formula I (R is H, benzoyl). EXAMPLE:1-(3-Deoxy-3-fluoro-beta-D-ribofuranosyl)-5-fluorouracil. USE:Antitumor agent. PREPARATION:A furanoside derivative of formula II (R<1> is alkoxy, halogen; R<2>, R<3> are protecting groups; Y is H, eliminating group) is fluorinated to introduce the fluorine atom in the 3-position. When needed, the product is deprotected. Then, residue of 5-fluorouracil group is introduced to give the compound of formula I. The fluorinating agent is suitably a fluorinated tetraalkyl or aralkylammonium and is used in the inert solvent in the form of a solution. The fluorination is conducted at 0 deg.C to room temperature. The compound of formula II has to be synthesized stereospecifically. Further, the hydroxyl groups other than the 3-position should be protected so that they are not fluorinated.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to an antitumor agent containing a difluorouridine derivative as an active ingredient.

Sugars containing fluorine atoms have attracted attention in recent years as important constituent units of pharmaceuticals and biochemical agents, and also because of their own physiological activity. For example, nucleosides that suppress fluorine-containing sugars are known as antiviral and antitumor agents.

Specifically, 3-deoxy-3-fluoro-α-D-xylofuranoside derivatives (J, A. Wright et al.

Carbohydrate Research, 18.
345-347 (1971).

Y,Fouron et al., J,Org,chem,, 3
9.1584-1570 (1970)), 5'-halonucleoside (JP-A-53-95982, D
E1G70588. Ding, M., 5avarese et al., B.
iochem.

Pharmacol, 34.3E11-387 (19
85)), etc., and examples of the difluoronucleoside include 2-deoxy-2,2-difluororibofuranoside derivatives (JP-A-59-175498, 3,5-dideoxy-3,5-difluoro-D- xylose (A,
B. Foster et al.

Carbohydrate Re5earch, shin, 1
88-171 (1989)).

Fluorine atoms have an extremely strong binding force to carbon atoms compared to hydroxyl groups, are inert and hydrophobic, and have an atomic size similar to that of hydroxyl groups. Therefore, replacing the hydroxyl group of sugar with a fluorine atom can be expected to have excellent effects in terms of antimetabolism and the like. On the other hand, as sugars, lipose and 2-deoxy lipose, which are structural units of nucleosides, have a wide range of applications, but the above-mentioned known fluorinated sugars
The fluorine atom is not substituted only at the steric position of the hydroxyl group of lipose or 2-deoxy lipose, for example, 2-deoxy lipose.
In deoxy-2,2-difluorolipotalanoside derivatives, fluorine atoms are present even in positions where hydroxyl groups were originally not present, and 3-deoxy-3-fluoro-β-D-xylofuranoside derivatives (formula [ml (see), there is no fluorine atom at the position where the hydroxyl group of lipoose exists.

It is known that the efficacy of these fluorinated sugar-containing nucleosides as antitumor agents is not high (for example, R.F., Bruns, Gan, J., Physi.
ol, Pharmaceutical, 58.873 (1980
), and the reason for this is presumed to be related to the steric configuration of the fluorine atom as described above.

On the other hand, 5-fluorouracil (5-FU
) and its derivatives are used. However, 5-F
U is highly toxic and cannot be administered in large doses, so its effectiveness is not sufficient, and FT-207 (tetrahydrofuryl 5-fluorouracil) is only as effective as 5-FU when administered in small doses; The problem is that the effective therapeutic range is narrow (N., Uehara et al., J.
pn, J, CancarRes, (cancer), 78.1
034 (1985)), and various other 5-FUJ conductors such as sugars having 5-FU residues have been proposed as antitumor agents, but these are not sufficient in terms of efficacy and safety.

The present inventors previously researched and considered the introduction of a fluorine atom into the steric position of the 3-hydroxyl group of Ripose, and as a result, discovered a novel 3-deoxy-3-fluoro-D-ribofuranoside derivative (patent application (See Sho Go-220188).

This novel nucleoside containing a fluorine-containing sugar was expected to have higher efficacy as a medicine than the above-mentioned known nucleoside containing a fluorine-containing sugar. Therefore, as a result of examining the pharmaceutical application of the above-mentioned novel fluorinated sugars into which various nucleobases have been introduced, it was discovered that compounds having a 5-FU residue have remarkable medicinal efficacy as antitumor agents.

The present invention relates to an antitumor agent containing a novel difluorouridine derivative represented by the following formula [I] as an active ingredient.

However, R: hydrogen atom or benzoyl group.

In the above formula [I], R is particularly preferably a hydrogen atom.This difluorouridine derivative can be used in combination with one ordinarily pharmacologically acceptable pharmaceutical additives. In addition, it can be used by adjusting the formulation to an appropriate formulation depending on the route of administration. For example, injectables may contain isotonic agents, buffers, solubilizers, preservatives, and the like. In addition, as an internal preparation, for example, excipients, binders, stabilizers, dispersants, etc. can be blended.

The method for producing the difluorouridine derivative represented by formula [I] in the present invention is not particularly limited, but it may be produced by the method described in the application related to the invention by the present inventors. Preferably, that is, by fluorinating a furanoside derivative represented by the following formula [rl] to introduce a fluorine atom at the 3-position, then after performing deprotection etc. if necessary, introducing a 5-fluorouracil residue. It is preferable to produce a fluoroadenosine derivative represented by the above formula [I].

However, R1: an alkoxy group or a halogen atom.

R2, R3: Protecting group.

Y: Hydrogen atom or leaving group.

R1 is preferably a lower alkoxy group, particularly a methoxy group,
Although R1 may be a halogen atom.

At the time of fluorination, R2 and R are preferably an alkoxy group, and the position thereof is preferably at the β position.
All of 3 are hydroxyl protecting groups, and both may be the same or different.

Among them, R3 is preferably an alkyl group or an aralkyl group, and particularly preferably a furalkyl group such as a benzyl group.
R2 is preferably a protective group other than an alkyl group, such as a trialkylsilyl group or an aralkyl group, and particularly preferably a t-butyldimethylsilyl group.Y may be a hydrogen atom, but the fluorine of the hydroxyl group bonded to the 3-position This is not necessarily easy, and fluorination is preferably carried out after introducing a leaving group. This leaving group is a group that facilitates fluorination after activating the 3-position hydroxyl group, such as methanesulfonyl group, trifluoromethanesulfonyl group, p-
) luenesulfonyl group, imidazolylsulfonyl group,
Examples include acetyl group and trimethylsilyl group. In particular, a trifluoromethanesulfonyl group has a high activation effect and is preferably used as a leaving group.

As the fluorinating agent, any known fluorinating agent may be used, but fluorinated tetraalkyl (or aralkyl) ammonium is particularly suitable. As the alkyl group, a lower alkyl group is suitable, and as the aralkyl group, a benzyl group is suitable, and the four alkyl groups and aralkyl groups may be different, or may consist of both an alkyl group and a full alkyl group. Preferably, fluorinated tetrabutylammonium is used; these fluorinating agents are usually used dissolved in an inert solvent such as tetravitrofuran. The fluorine reaction is usually carried out in an inert solvent at a temperature of several tens of degrees Celsius or less, and preferably at a temperature of about θ°C to room temperature.

The furanoside derivative represented by the formula [T1] needs to be stereospecifically synthesized. In addition, other hydroxyl groups except for the 3-position hydroxyl group must be selectively protected so as not to undergo the fluorination reaction.For these reasons,
The furanoside derivative represented by formula [11] is preferably synthesized by the following route, where R1 is an alkoxy group.

R4 represents an alkylidene group, preferably an alkylidene group having 7 or less carbon atoms, and particularly preferably an impropylidene group. The compound of formula (1) is a β-D compound in which the hydroxyl groups at the 3- and 5-positions are protected by this alkylidene group. The hydroxyl group at the 2-position of this compound is protected with the above-mentioned R3, especially the benzyl group to obtain the xylofuranoside derivative represented by formula (2). Next, R4 is removed, and the 3- and 5-position This deprotection of the hydroxyl group at the position can be easily carried out in the presence of an acid catalyst. As the acid catalyst, inorganic acids such as sulfuric acid and hydrochloric acid and organic acids such as acetic acid can be used, but it is convenient to use acetic acid. At this time, R3 must not be eliminated, and therefore the above-mentioned protecting group is employed. The hydroxyl group at the 5-position of the resulting compound represented by formula (3) is selectively protected by a protecting group R2.
, in particular, by protecting with a t-butyldimethylsilyl group, a compound represented by formula (4) can be obtained.

Next, a leaving group Y' is introduced into the hydroxyl group at the 3-position to obtain the desired compound represented by formula (5).

The compounds represented by these formulas (4) and (5) are one type of compounds represented by the formula [R1]. The reason for adopting this reaction route is that the reactivity of the 2- and 3-position hydroxyl groups is similar, so it is necessary to introduce a protecting group only to the 2-position hydroxyl group, and the 3-position hydroxyl group This is due to the need to maintain the three-dimensional position.

By fluorinating the furanoside derivative represented by the above formula [11], the fluorine atom is bonded to the sterically opposite side of the OY group, and OY is eliminated.

Usually, at the same time as this fluorination, the protecting group of the 5-position hydroxyl group is removed, and the fluorinated product of the following formula (6) is obtained.
The hydroxyl group at the position is deprotected to obtain a diol of the following formula (7). The protective group R3 for the hydroxyl group at the 2-position is removed by hydrogenation or the like.

For example, when R3 is a benzyl group, it is eliminated by hydrogenation using palladium black as a catalyst. The following formula (7)
When introducing a 5-fluorouracil residue into a compound, it is usually necessary to protect the hydroxyl groups at the 2- and 5-positions again. As this protecting group, an acyl group such as an acetyl group or a benzoyl group can be employed.

Introduction of 5-fluorouracil residues can be carried out in various ways. For example, one reference (Wright, Carbah
yd-rate Re5search, 18,345 (
1971) may be employed. This method is
This is a method in which the hydroxyl group or its derivative group at position 1 is substituted with a bromine atom, and this hydrogen atom is substituted with a residue of a nucleobase. Specifically, two hydroxyl groups of the compound represented by the above formula (7) are protected, R1 is converted to a bromine atom with a brominated hydroxyl-acetic acid solution, and then this bromide is converted into a 5-fluorouracil residue. Substitute with a group.

Finally, by removing the protecting group, the difluorouridine derivative of the present invention is obtained.

Hereinafter, the present invention will be specifically explained with reference to Examples, but the present invention is not limited to these Examples. Synthesis examples This is an example.

Synthesis example ■ Methyl 2-0-benzyl-3,5-0-impropylidene-β-D-xylofludge F [In formula (2), R1 is a methoxy group, R3 is a benzyl group, R4
is an impropylidene group].

Methyl 3.12.8 g (81,8+s mol) of 5-0-impropylidene-β-D-xylofuranoside,
Benzyl bromide (21.1 g) was added to a suspension of silver oxide (15.0 g) in N,N-dimethylformamide and stirred at room temperature for 36 hours. The reaction solution was filtered, water was added, and extracted with chloroform. The organic layer was washed with water, dried over magnesium sulfate, and concentrated. 2.8 g (yield: 88%) of benzyl ether t purified by column chromatography was obtained.

IH-NMR (CDCIs, ): δ1.38 (s,
8H), 3.41 (s, 31).

3.8-4.5 (a+, 5H), 4.5El (s, 2
H), 4.98 (s, IH).

7.32 (s, 5H).

(2) Synthesis of methyl 2-0-benzyl-β-D-xylofuranoside [a compound in which R1 is a methoxy group and R3 is a benzyl group in formula (3)].

Methyl 2-0-benzyl-3,5-0-impropylidene-β-D-xylofludge F 30.1 g (0,1
0 mol) was dissolved in acetic acid (EfOsQ)-water (24m<2) and reacted for 1 hour on a 50°C water bath. 5 teacups
The low boiling point substances were discharged while maintaining the temperature at 0°C.

Purified by column madograph to give 20.9 g of diol (yield: 8
0%) was obtained.

Rt 0.40 (benzene-ethyl acetate = 1:1)
.

■ Methyl 2-0-benzyl-5-0-t-butyldimethyl-β-toxylofuranoside [in formula (4),
Synthesis of a compound in which R1 is a methoxy group, R2 is a t-butyldimethylsilyl group, and 1173 is a benzyl group].

20.9 g (82 mmol) of the diol synthesized in Synthesis Example ①
), M,N-dimethylformamide (80m+(2
) and added imidazole (18.8 g). To this solution was added 12.4 g of t-butyldimethylsilane chloride in N,N-dimethylformamide (80 mQ) at 0°C.
It was added dropwise over 0 minutes. After stirring for 3 hours, post-treatment was carried out according to a conventional method. Column chromatography purification gave 2 g of silyl ether 3o (yield 100%).

'H-NMR (GDCh): δ0.10 (s, 8H),
0.81 (s, 9H).

3.37 (s, 3H), 3.9-4.1 (+o, 3H
), 4.2-4.4 (m, 3H), 4.81 (g
, 2H), 4.93 (s, IH), 7.32 (s,
5H).

■ Methyl 2-0-benzyl-3-deoxy-3-fluoro-β-D-ribofuranoside [in formula (6),
Synthesis of a compound in which R1 is a methoxy group and R3 is a benzyl group].

Methyl 2-0-benzyl-5 synthesized in Synthesis Example ① above
-D-t-butyldimethylsilyl-β-D-xylofuranoside13. 11.4 g of 2,6-lutidine was added to a solution of Og (35.0 mmol) in dichloromethane (80d), and the mixture was cooled to 0°C. Triple olomethane sulfuric acid anhydride (20.0 g) was added dropwise thereto over 15 minutes, and the reaction was continued for an additional 30 minutes. After post-treatment by adding ice, 18.8 g of the crude product was taken out using short column chromatography.

This material was dissolved in tetrahydrofuran (eOm(2)), and 92 m (2) of a tetrahydrofuran solution (f-1,0) of fluorinated tetrabutylammonium was added dropwise at 0°C over 20 minutes. After stirring for a period of time, tetrahydrofuran was distilled off and treated with saturated ammonium sulfate ice solution. Column chromatography was performed to obtain 5.4 g of the title fluorinated product.

19F-NMR (CDCh): (CChF standard) -20
7,1(ddd,j53.7.22.0.13.4H
z).

IH-NllIR(C[IC1z): δ3.47(s
, 31(), 4.0-4.2(a+.

2H), 4.55(s, 2H), 4.8-5.2(
m, 5H).

7.33 (s, 5H).

IR (CHCh) 3300c++-1゜■ Methyl
2,5-di-0-benzoyl-3-fluoro-β-D-
Synthesis of ribofuranoside.

5.4 g (2
1.1 mmol) was dissolved in 70 mQ of ethanol, and 5%
- Hydrogenation was carried out at room temperature and normal pressure in the presence of 5.5 g of palladium black. After 10 hours, the mixture was filtered through Celite 545 and concentrated.

The crude product was dissolved in 35 ml of pyridine, 6.1 g of benzoyl chloride was added, and the mixture was reacted at room temperature for 36 hours.

After distilling off pyridine, column chromatography purification was performed to obtain methyl 2,5-di-0-benzoyl-3-fluoro-β-D.
-2.2g of ribofuranoside was obtained. This dibenzoyl compound is a compound of formula (7) (R1 is a methoxy group) in which the hydroxyl groups at the 2- and 5-positions are protected with benzoyl groups.

19F-NMR (CDCh): (CChF standard) -21
1,8(ddd.

j-53, 2, 18, 1, 4, 91 (z).

(2) Synthesis of 1-(3-deoxy-3-fluoro-β-D-ribofuranosyl)-5-fluorouracil [a compound in which R is a hydrogen atom in formula (1)].

0.80 g of the tribenzoyl compound synthesized in the above synthesis example ①
(1,8+s mol) to acetic acid (2,8+s mol)
-Dissolved in acetic anhydride (0,12811(2). Add 30% hydrogen bromide-acetic acid solution (8.8 mQ) to this and stir at room temperature for 3 hours. After completely distilling off acetic acid and acetic anhydride, , dissolved in toluene (20+aQ) and added to a toluene suspension of 5-fluorouracil mercury (0,82 g).
The mixture was heated to reflux for an hour. Short column purification gave 0.1 g of uracylated product.

19F-NMR (GDCh): (CGhF standard) -18
1,3(s).

-210,4(ddd, j=59.7.43.94.
18.07Hz).

The product obtained above was dissolved in methanol (4 mQ),
1 tosodium methoxide-methanol solution (0.34
mQ) was added, and the mixture was heated under reflux for 1 hour. The methanol was distilled off and neutralized with 2N acetic acid to give the final product, the title compound (very hygroscopic) (0.02 g).

19 F-NMR (acetone-d6): (CCI F yield standard 173.05 (s), -209,77 (dd
d, j section 54.40°21.48.12.08Hz
).

IH-NMR (acetone-d6): δ3.58 (d,
J-5,4Hz.

2H), 3.5-5.1 (m, 5H), 4.9
(dt, j-54, 7° 4.7Hz, IH), 7.8
2 (s, IM), 7.70 (g, IH).

IR (KBr tablet) 3400.1700.1850
am-1゜Example Mouse leukemia cells (L 5178Y) were seeded into 24-well microwells at 1105 cells/well, and treated with 10% tallow serum and kanamycin (50 μg/well).
Fluorouridine synthesized in the synthesis example as shown in the table was added to the RPM11640 medium containing
μg/raQ, 1.0μg/laQ, 3.0μg/
mQ, 10.0μg/! 1 Qe and cultured for 2 days under 5% carbon dioxide and 37°C conditions. Cell proliferation was measured by trypan blue staining, and the inhibition rate was determined. The 50% growth inhibition concentration and inhibition rate of the fluoroadenosine derivative in this test tube are shown in the table below.

Claims (1)

[Scope of Claims] 1. An antitumor agent containing a difluorouridine derivative represented by the following formula [I] as an active ingredient. ▲There are mathematical formulas, chemical formulas, tables, etc.▼・・・［I］ However, R: hydrogen atom or benzoyl group.